Method for supplying multiple metal streams to a continuous casting mold



A. MICHELsoN 3.456.713 METHOD FOR SUPPLYING MULTIPLE METAL STREAMS TO A CONTINUOUS CASTING MOLD July 22, 1969 3 Silesia-Sheet 1 Filed Sept.

INVENTo ANATOL MICHELSON BY /V/eqz, 7M? /lq July 22, 1969 A. MICHELsoN 3,456,713

METHOD FOR SUPPLYING MULTIPLE METAL STREAMS T0 A CONTINUOUS CASTING MOLD Filed sept. 7, 1966 s sheets-sneet z INVENTOR. ANATOL MICHELSON BY MW, wm, z w.,

ATTORNY-S U.S. Cl. 164-82 3 Claims ABSTRACT OF THE DISCLOSURE A method of continuously discharging two streams of molten metal into the mold of a continuous casting machine. The method comprises utilizing two ladles each associated with nozzle means for providing two separate streams from each. One of the ladles is positioned above the mold and its contents supplied to the mold in two streams. As it begins to empty, it is shifted laterally so that only one of its streams is conducted to the mold. Simultaneously, the other ladle is brought into position so that one of its streams is conducted to the mold. As fiow from the first ladle terminates, both ladles are shifted so that both of the streams from the second ladle are conducted to the mold.

This invention pertains to the art of continuous casting and more particularly to the casting of separate heats or ladles of molten metal without interruption from one heat to the next.

The invention will be described with particular reference to the casting of wide slabs where more than one stream of molten metal is directed into the mold Simultaneously, however, it should be appreciated that it is equally applicable to the casting of other shapes, such as ovals, rounds, squares or the like.

Heretofore, so-called uninterrupted continuous casting has involved the use of several ladles in which one ladle is pouring as a fresh one is brought up and pouring is begun from it as the metal from the first is being exhausted. By recycling ladles in this manner, the fiow of metal to the mold may continue substantially without interruption. The ladles are not poured directly into the mold but instead are tapped into an intermediate refractory vessel or tundish from which the molten metal is then conveyed to the mold. To achieve a quick interchange of ladles, it has been proposed in the past to support the ladles on carriages traveling on an elevated trackway above the pouring fioor. The ladles can be lifted out or lowered onto the carriages by means of an overhead crane. In one prior art arrangernent, a pair of tundishes and trough members, one associated with each ladle, is pivoted on a column which extends parallel to the casting axis. Molten metal is supplied substantially without intcrruption to the mold by turning the tundishes and trough members in a manner synchronized with the expiration of molten metal from one ladle and the initial pouring from the other.

However, such prior art apparatus is unsuitable for uninterrupted continuous casting of wide slab ingots. In casting wide, rectangular slabs, for example, approximately 5 feet wide by 6 inches thick, at least two streams of molten metal spaced a considerable distance apart are ts atent 0 3,4%,713 Patented July 22, 1969 used to supply the mold requirements for metal. The rotational prior art arrangement would cause the parallel metal streams to move through an arc which is wholly inconsistent with the geometry of the slab mold and would therefore be unworkable.

Moreover, with at least two streams feeding the mold, prior art trough members cannot avoid feeding the contaminated and cold metal initially to the mold or prevent dripping when the tundish is moved away from the mold.

The present invention accomplishes the pouring of at least two streams of molten metal at the same time, synchronizing the movement of troughs, tundishes and ladles so that substantially uninterrupted slab casting is achieved.

In accordance with the invention there is provided a mold adapted to receive molten metal in at least two pouring locations. A pair of tundishes, each having two pouring nozzles, are movable longitudinally labove the mold so as to intersect with the two pouring locations. The spacing of the tundish nozzles is so related to the mold dimensions and pouring locations that movement of the tundishes Ielative to the mold brings about a displacement of one nozzle of one tundish beyond the mold side wall as a nozzle of the other tundish is moved labove the mold. The shfting of the tundishes is synchronized with the depletion of metal from a pouring ladle supplying one of the tundishes and the start of pouring from another ladle supplying the other tundish so that the supply of the parallel streams of molten metal to the mold is not substantially interrupted.

The main object is to provide a method and apparatus for casting wide slab ingots substantially without interruption.

Another object is to provide a method of shfting a pair of tundishes in rectilinear fashion so as to achieve continuous fiow at two parallel mold pouring locations.

Still another object is to provide a continuous casting pouring method and apparatus in which half of the equipment is inactive most of the time enabling repairs to be made without interruption of the casting cycle.

These and other objects will be more fully appreciated by referring to the following description and drawings wherein:

FIGURE 1 is apartially sectioned side elevational view of pouring apparatus in accordance with the preferred embodiment of the invention;

FIGURE 2 is a top view of the pouring apparatus in FIGURE 1 showing the position thereof when the molten metal is being supplied to the mold entirely by one of the ladles and tundishes;

FIGURE 3 is a schematic view showing an intermediate pouring position of the apparatus in FIGURE 1 in which molten metal is being supplied in part by both ladles and both tundishes during the transition;

FIGURE 4 is a schematic view similar to that in FIG- URE 3 showing the position of the ladles as the pouring responsbility is shifted from one ladle to the other; and

FIGURE 5 is another schematic view showing the position of the ladles after the transition is completed.

Referring to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same, FIGURES 1 and 2 show a pouring apparatus 10 positioned over a slab mold 12. The pouring apparatus moves longitudinally relative to the mold 12 on a carriage 14 having rollers 15 mounted on rails 16. The mold 12 has a casting cavity 18, the long axis of which is generally parallel to rails 16. Two bottom pour ladles 20, 22 are transported by the carriage 14 and can be lifted into and out of position by an overhead crane.

Two tundishes 30, 32 each include a oovered pouring chamber 33 communicating through 'a port 3'4 with a chamber 35. The ch'amber 35 of each tundish 30, 32 projects laterally below each ladle spout 37, 38 while the pouring chambers 33 extend longitudinally above the mold cavity 18. According to the invention, at least two pouring nozzles 46, 47, 46', 47' project from each pouring Chamber 331 at laterally spaced pouring locations although for particularly wide slabs more may be needed. In addition to longitudinal movement on carriage 14, each tundish 30, 32 is adjustable laterally of the mold by traversing mechanisms indicated generally at 36. Thev outside nozzles 47 and 47' only of each tundish both have stoppers 50 projecting through the refractory cover of the pouring chamber 33 and include Operating mechanism's, generally indicated at 52, for imparting Vertical movement thereto so las to shut off flow through the nozzles 47, 47' when desired.

Associated with each tundish 30, 32 is a trough 54, 54' having a refractory lining 55. Each trough is pivoted at 57 to a bracket 58 mounted beneath the carriage 14. As shown in FIGURE l, eachtrough 54, 54' is movable between 'the tundishes and the top of the mold 12. Each trough is inclined downwardly so that the end 60 swings in an zarc above 'a refractory vessel 65 and is roughly triangular in shape having an end 62 sufficiently wide to span the distance between sets of nozzles 46, 47, 46', 47'. The vessel 65 is wider at the back wall 66 than at the front wall 67 where pouring lip 68 is located so as to accommodate the sweep of the trough ends 60.

A more complete understanding of the method of operation in accordance with the invention may be had by referring to the following description. Briefly, the method nvolves pouring until one ladle is nearly empty and then bring up a fresh ladle and continuing to pour it by shifting the apparatus 10 relative to the mold. When flow diminishes from the first ladle, the mold requirements are supplied by the fresh ladle. Thus, by recycling fresh ladles and shifting the pouring apparatus 10 back and forth, uninterrupted casting is obtained from a plurality of ladles. Starting with the cycle as shown in FIG- URE 2, ladle 22 is full of molten metal and is positioned on the carriage 14 over the mold 12. The pouring spout 37 of ladle 22 is discharging directly into the chamber 35 of the tundish 30. The transversing mechanism 36 has previously been adjusted to position the tundishes 30, 32 in line with the mold cavity 18. At this time the ladle may not be in position, but rather is being prepared at some other remote location and Will be brought up when ladle 22 approaches an empty condition. During casting, the troughs 54, 54' are pivoted out of the way of the two nozzles which are Pouring, i.e., in FIGURE 2 trough 54 is swung to the right providing a clear path for the nozzles 46, 47. If desired, troughs 54, 54' may be swung into position under both nozzles 46, 47 or 46', 47' to conduct the first portion of metal into vessel 65 if it is felt that contamination is likely at the start of casting.

As casting proceeds and the metal held by Originally full ladle 22 begins to run out, a fresh ladle 20 is brought up and put in position over tundish 32. Before flow through nozzles 46, 47 has diminished appreciably, however, the carriage 14 is slowly started to move bringing the inside nozzle 46' of tundish 32 closer to the mold cavty 18 while moving the outside nozzle 47 of tundish 30 an equal distance toward the opposite side of the mold. Due to the spacing between nozzles, nozzle 46' will have been moved to within the boundary of the mold cavity 18 by the time nozzle 47 is leaving at the opposite 4 side. Before stopper 50 shuts off flow from nozzle 47, pouring commences from the fresh ladle 20 into tundish 32 and nozzle 46'. This transition period can best be visualized by referring to the diagrams in FIGURES 3-5. Referring to FIGURE 3, pouring is now taking place from both ladles 20, 22. At this time, all of the metal flowing into tundish 30 from ladle 22 is diverted to nozzle 46 which has taken up the position formerly occupied by nozzle 47 and likewise, all the metal flowing into tundish 32 from ladle 20 is diverted through nozzle 46' which has taken up the position formerly occupied by nozzle 46. Both nozzles 47, 47' are now idle. Pouring and shifting -of carriage 14 continues without interruption until fiow through nozzle 46 is in danger of being diminished or the metal contaminated by slag impurities from the emptying ladle 22. In FIGURE 4 the carriage 14 has been shifted to the point where nozzle 46 is about to move outside the mold cavity 18 while at the same time, nozzle 47' is moving within it. As nozzle 46 moves beyond the mold cavity, trough 54 is positioned under it to divert the metal and slag flow from the emptying ladle 22 into vessel 65; while simultaneously, the stopper 50 for nozzle 47' is opened to permit full parallel flow int-o the 'mold 12 from both nozzles 46', 47'. In FIGURE 5, movement of the carriage 14 has continued until the nozzle 46' takes up the position Originally occupied by the nozzle 47 and nozzle 47' that position first occupied by nozzle 46. As may be appreciated from the above, the process continues by bringing a fresh ladle to replace the empty one and moving the carriage 14 in the opposite direction thus supplying metal at both pouring locations of the mold in substantially uninterrupted fashion.

Having thus described a preferred embodiment of the invention and its method of operation, it will be appreciated that various modifications and changes may be made by those skilled in the art without departing from the spirit of the invention as defined by the appended clai'ms except insofar as they are limited by the prior art.

Having thus described my invention, I clairn:

1. A method of discharging ladles of molten metal sequentially into the mold of 'a continuous casting machine without interruption comprising the steps of:

providing a first substantially full ladle having nozzle means associated therewith for conducting molten metal from said first ladle in first and second parallel streams;

positioning said first ladle and its associated nozzle means above said mold and conducting the molten metal from 'said first ladle to said mold in said first and second parallel streams;

providing a second substantially full ladle having nozzle means associated therewith for conducting molten metal from the said second ladle in third and fourth parallel streams;

prior to termination of flow from said first ladle, Shifting said first ladle and its associated nozzle means laterally so only said second stream is in position to conduct molten metal to said mold and, substantially simultaneously, bringing said second ladle and its associated nozzle means to a position above said mold and conducting molten metal to said mol-d from said second ladle in said third stream;

continuing to supply molten metal to said mold from both of said ladles from said second and third streams respectively; and,

as flow from said first ladle begins to diminish, shifting both said ladles and their associated nozzle means laterally to a position wherein only said second ladle and its nozzle means is in position above said mold, and conducting metal from said second ladle to said mold in said third and fourth streams.

2. The method as defined in claim 1 including the step of stopping said first stream as said first ladle and its associated nozzle means are shifted laterally.

5 6 3. The method 'as defined in clam 1 including the step 3,273,208 9/ 1966| Greenberger 164-281 of starting flow of said fourth stream prior to the time 3,344,847 10/1967 Beemer 164--281 said second ladle and its associated nozzle means is in position above said moId. FOREIGN PATENTS 181,027 2/1955 Austria.

References Cited 5 I SPENCE 0 ERH L-SER P' E UNITED sTATEs PATENTS R V O t mary mmm I 336 767 4/1920 Warren 164 337 X R. SPENCER ANNEAR, Assistant Examiner 1,401,928 12/1921 sheldon 164-337 X US C1 XR 2,732,6o1 1/1956 Junghans 164-82 10 164 281 3,218,682 11/1965 Namy 164--337 

